Kitchens and baths contribute large amounts of water vapor to home air space. Install and maintain kitchen range hood and bathroom vent fans of sufficient capacity. Locate intakes where they can capture the most moisture.

If your bathroom fan has an on/off switch, modify it to always operate when the light is on. Showering with the fan off can force moisture into the bathroom walls and cause both fungal growth and structural decay.

Install an air-to-air energy recovery ventilator to provide low cost outdoor fresh air supply during heating and air conditioning seasons.

Have, gas appliances (stove, water heater, furnace) professionally examined once a year, as well as cleaned and maintained when necessary.

Routinely check all gas burners to see that they burn with a blue flame. Make sure that pilot lights are lit.

Install a CO (carbon monoxide) monitor, and check it routinely.

If you have a ducted HVAC (Heating Ventilating and Air Conditioning) system, make sure that the fresh air intake, on the exterior of your home is located well above ground and upwind from any local contamination sources such as idling motor vehicles.

Routinely clean coils and drain pan on window air conditioners.

Ultra-sonic cool mist portable humidifiers should only be filled with distilled water, as they tend to disperse contaminants in tiny droplets that may deposit in the lungs.

Don't allow smoking in your home. Second-hand tobacco smoke has been shown to be a carcinogen, as well as a lung irritant.

Schedule a fall tune-up to ensure your furnace is functioning properly according to the specifications in the owner's manual. You should also have a professional furnace duct cleaning service inspect and clean the supply and cold air return ducts in your home. Don't forget to check your fireplace flue.

Check the caulking and weather stripping on or around exterior doors and windows. Replace any that is worn, cracked or missing.

Humidifiers are effective at counteracting the discomforts of excessively dry air, but if not properly maintained, they can become breeding grounds for bacteria and molds, dispersing them into the air. Clean your humidifier regularly with a quality-cleaning agent.

Planning to re-carpet? New carpeting vapors can cause irritation. Request a small sample and put it in a tightly sealed jar. After a day or two, open the jar and smell the air in the jar. If the odor offends you, you may want to consider another choice.

If your holiday plans include a hotel stay, bring your own blanket and pillow. While the housekeeping staff washes sheets between guests, bedspreads, blankets and pillows are changed less frequently, increasing the potential for exposure to dust mites, perfumes and deodorants.